ABSTRACT
This chapter utilizes the literature base and adds results of current research dealing with the impacts of various facets of soil N management on the quality of surface runoff and subsurface water. Nitrogen concentrations in surface runoff from pastures were also usually found to be below the maximum levels set for human health. Surface runoff is dependent on amount and intensity of precipitation, antecedent soil moisture, soil properties, and slope, as well as management factors such as tillage, crop residue, and cropping systems. Surface runoff and infiltration are closely related. Various intermediate conservation tillage practices will have intermediate effects on the shift of water flow from runoff to infiltration. Conventional tillage disrupts the surface soil structure and buries a major portion of the residue cover. The impacts of tillage, crop management, and fertilizer management are quite interrelated, especially their impacts on soluble N, which is moved via subsurface flow.
